* {
  box-sizing: border-box;
}

body {
  padding: 0;
  margin: 0;
  font-family: Arial, Helvetica, sans-serif;
  display: flex;
  align-items: center;
  justify-content: center;
  height: 100vh;
}
canvas {
  cursor: crosshair;
  width: 100%;
  height: 88%;
  display: block;
}
.container {
  width: 45vw;
  height: 78vh;
  border: 2px solid #4682b4;
  position: relative;
}

.op {
  position: absolute;
  bottom: 0px;
  width: 100%;
  height: 12%;
  background-color: #4682b4;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.left {
  margin-left: 20px;
  display: flex;
}

.item {
  width: 50px;
  height: 50px;
  background-color: white;
  font-size: 40px;
  line-height: 50px;
  text-align: center;
  margin-right: 10px;
  cursor: pointer;
}
